Salmonid or nonsalmonid lakes: predicting the fate of northern boreal fish communities with hierarchical filters relating to a keystone piscivore

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Spens, Johan, Ball, John P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2008
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Esox lucius; Northern pike; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1139/f08-103; http://www.nrcresearchpress.com/doi/full-xml/10.1139/F08-103; http://www.nrcresearchpress.com/doi/pdf/10.1139/F08-103

We determine if lacustrine salmonids show large-scale patterns of coexistence with the keystone predator northern pike ( Esox lucius ) and test an approach to predict fish communities using coexistence rules set in the context of three hierarchical filters that a species must pass to be present. The mutually exclusive species distribution patterns that we detected among 1029 lakes were repeatedly verified from results of whole-lake interventions with rotenone and introductions. Essentially, pike did not coexist with self-sustaining salmonid populations in lakes. High connectivity to pike (derived from maps) largely predicts the absence of lacustrine salmonids. Our analysis strongly suggests that pike prevented self-sustaining populations of brown trout ( Salmo trutta ), Arctic char ( Salvelinus alpinus ), and brook trout ( Salvelinus fontinalis ) in lakes. High connectivity to pike resulted in nonsalmonid lake fish communities, most often including both European perch ( Perca fluviatilis ) and roach ( Rutilus rutilus ). Our analysis suggests that if pike were not present in many boreal lakes where they now dwell, salmonid fish assemblages would prevail, a sharp contrast from the present pike-driven homogenized state with mainly nonsalmonid fish communities.